Insufflatory resuscitation of a newborn baby that has not breathed presents many problems. These are dependent not only on the size and prematurity of the neonate, but on the amount of fluid which is present in the alveoli of the lungs, and the absence of the functional residual capacity (FRC). Before adequate gaseous exchange can take place the fluid must be driven out of the alveoli and the FRC established. Transpulmonary pressures as high as 80 cm H20 may be necessary. This places a unique demand on a resuscitator which can be used safely at birth. It must be able to achieve such pressures without injuring the lungs; yet once the FRC has been established, it must be able to adapt itself to the differing ventilatory requirements, without altering the blood chemistry of the neonate.S. Afr. Med. J., 48, 628 (1974)